1. Field of the Invention
The invention is drawn to an apparatus for improving both seed quality and the flow characteristics of difficult to handle, entangled seed material.
2. Related Art
Unprocessed seed, such as the seed of various grasses, is usually a heterogeneous mix of stems, leaves, chaff, awns, hairs, empty glumes, and seed of various size and quality. Natural dispersal agents such as hairs and awns tend to cling to each other, bridging-over and causing the seed to adhere in a mass. These masses make uniform dispensing and placement during planting difficult. Moreover, gravitational separation of the seeds by differential mass and densities often occurs during seed storage and transport, and particularly in the drill box, often resulting in non-uniform seeding rates and stand failures. Extensive and costly processing of the seed is typically required to produce a product which is clean and substantially pure.
Prior processes for the treatment of chaffy seed grasses have included the use of a hammer mill to chop up or break-up the grass stem, with subsequent seed cleaning treatments to debeard and deglume the seed. However, the efficacy of hammer mills is typically low, and such devices may damage the seed. Examples of previously known devices including some of the general structural and operational features of the instant invention are disclosed in U.S. Pat. Nos. 640,793, 2,011,365, 2,416,008, 3,087,618, 3,347,373, 3,837,490, 4,030,606 and 4,340,469.
More recently, Beisel (U.S. Pat. No. 4,533,469) has developed an apparatus for removing stems and cleaning (i.e., degluming and debearding) grass seeds without seed damage. Removal of stems and cleaning is effected in this apparatus by a rotating cylindrical drum having a wire mesh body, which operates in cooperation with a vibrating, elongated sieve assembly. Beisel has also developed an apparatus for cleaning and classifying seeds utilizing a skewed Coanda jet effect. A seed stream is accelerated and discharged horizontally through a duct having a downwardly curved trough or Coanda surface at its outlet. Light materials such as seed hulls and trash follow a low trajectory and are separated from the heavier particles such as seeds, which follow progressively higher trajectories.
However, despite these improvements, the need persists for devices effective for conditioning and classifying seed.
We have now invented an apparatus and method for conditioning and/or classifying seed utilizing the Coanda effect and momentum discrimination. The invention is particularly useful for separating whole, chaffy seeds from lightweight extraneous material such as one or more of lint, dust, fuzz, chaff, and trash. The apparatus includes a seed conditioning/classification unit having a conduit which is defined by upper and lower surfaces and which has an outlet at one end. The central axis of the conduit at this outlet is generally horizontal. An inlet to the conduit is spaced upstream from the conduit""s outlet for providing a crude particulate feed stream of the material to be conditioned which is entrained in a pressurized gas stream. To effect conditioning and classification, a convexly curved Coanda surface is provided adjacent to and curving upwardly from the upper surface of the conduit at the outlet. As the crude particulate feed stream is discharged from the outlet, it is conditioned (i.e., separated) by the Coanda effect into a first outlet stream of the entraining gas and lightweight extraneous materials, which is channeled approximately along or parallel to the Coanda surface, and a second stream of relatively heavier materials such as seeds, which is expelled approximately parallel to the central axis of the conduit at the outlet. Moreover, the seeds which are expelled from the conduit are also classified (i.e., separated into discernible fractions of seeds of different densities) by momentum discrimination, with higher density, high quality seeds being propelled farther from the conduit outlet than seeds of lower quality and density.
When handling unprocessed chaffy seed, particularly tough chaffy seeds such as Texas bluegrass, which tend to adhere together and form dense seed clumps, the apparatus preferably further includes a preconditioning unit and/or raw seed feed metering device or conveyor. The pre-conditioning unit is adapted for breaking up small seed clumps and for dislodging hairs, awns, and extraneous appendages from whole seed which are typically present in a chaffy seed material. Pre-conditioned seed from this unit may then be used as the feed for the conditioning/classification unit. A raw seed conveyor may also be provided for delivering the raw seed to the pre-conditioning unit. The conveyor may be adapted for shearing large clumps of seed into individual seeds or smaller fractions which may be metered into the preconditioning unit at a uniform rate.
In accordance with this discovery, it is an object of this invention to provide an improved apparatus and method for conditioning and/or classifying seed, particularly seeds of grasses and most particularly of chaffy seed grasses.
Another object of this invention is to provide an apparatus and method for removing and separating lint, dust, fuzz, chaff, and other trash from seeds.
Yet another object of this invention is to provide an apparatus and method for classifying seed.
Still another object of this invention is to provide an apparatus and method for producing free-flowing seed of uniform size and quality.
These and other objects and advantages of the invention will become readily apparent from the ensuing description.